1. Field of the Invention
The present invention relates to a channel switching control in a mobile telecommunication system of a multiple zone configuration.
In a mobile telecommunication system of a multiple zone configuration, some of the service areas which can communicate with a base station will have heavy or light loads. Further, the degree of deterioration of the received level of a mobile station will differ according to the speed of movement of the mobile phone, car phone, or other mobile station or the topography of the location where it is present. Accordingly, there will be mobile stations with a sufficient margin of time from when they send channel switching requests to when they can no longer maintain the desired quality and mobile stations which have no such margin of time. Accordingly, it is desired to enable channel switching without allowing the quality of service to fall.
2. Description of the Related Art
As will be explained in detail later with reference to the drawings, in a mobile telecommunication system of a multiple zone configuration, the channels have to be switched when a mobile station moves across zones. In this case, since there are a limited number of speech channels in any one zone, when for example there is just one idle channel and there is a request for channel switching from a mobile station with a margin of time until the quality of service becomes worse than a predetermined level and a request for channel switching from a mobile station with no margin of time until the quality of service becomes worse than the predetermined level, the conventional type of base station control equipment would assign the idle channel to the mobile station which first made the channel switching request. Accordingly, the mobile station which requested the channel switching just after that would find its channel switching request rejected due to the lack of an idle channel.
When this situation occurred, the mobile station with no margin of time until the quality of service deteriorated beyond the predetermined level would not be able to switch channels and therefore there was the problem that the predetermined quality of service could not be maintained a short time later and service would remarkably deteriorate.